With the continuous development of modern microwave millimeter wave communication systems, for example, the rapid development of the mobile communication system, phased array radar, satellite communication, satellite navigation, electronic countermeasures and precision guidance systems and equipment, the high-speed broadband technology has become a development trend. This new technology often requires the communication system possess multi-carrier and large-dynamic-range characteristics, so the linearity of the microwave devices is very demanding. Therefore, for a microwave device component such as a wide-bandgap semiconductor, ultra-wideband mixer and high-power low intermodulation connector, their nonlinear characterization and modeling problem has attracted much attention of the industry. The general way to study this problem is to test their nonlinear behavioral characteristics based on the black-box theory.
The existing approach to testing the nonlinear characteristics of microwave device components is to model their behavioral-level nonlinear characteristics by regarding the microwave device components as a “network” under test with N ports, where the concept of the network is derived from the “black box model.” The famous nonlinear models include the X-parameter Model and the Cardiff Model. The X-parameter Model was developed by Dr. Jan, mainly launched by Keysight Technologies (formerly known as Agilent Technologies Inc.) and modeled and processed by the ADS software; the Cardiff Model was established by Mesuro Limited in the United Kingdom and is mainly launched by R&S (Rohde & Schwarz) at present. However, these models are based on single-frequency signal excitation, and thus cannot fully express the nonlinear behavioral characteristics of the device components or the behavioral parameters of the device components such as passive component intermodulation distortion, power amplifier intermodulation distortion, mixer frequency conversion loss and divider frequency division loss. Therefore, in the field of microwave communications, there is an urgent need for a model and testing method that breaks through the limitation of single-frequency excitation, predicts the nonlinear behaviors of the microwave device components and may be used for system design.